Radio frequency (RF) energy is a significant source of interference in electronic equipment. Spurious RF signals may be coupled onto signal carriers, circuit boards, and electrical components.
High frequency noise caused by wireless devices and other oscillating equipment can affect signals that are transmitted through wires and cables. This interference can be reduced by filtering the signals within a device or by electrically shielding electronics and cables from the interference. In some applications, filtering of signals is difficult due to the need to pass high frequency communications, and can be further complicated by limitations in capacitance and inductance required by some certifications, such as industry standards for intrinsic safety or other applications. A conductive enclosure that creates a faraday shield can be used to protect the device's electronics, and a shielded cable can be used to protect wiring. However, improper connections between the enclosure and the shield of the cable can eliminate much of the benefit provided by the shielding and introduce new issues such as ground loops.